A cellular wireless communication system mainly comprises a Core Network (CN), a Radio Access Network (RAN) and a User Equipment (UE). The CN takes charge of transactions of a non access layer; the RAN includes a base station or a base station and a base station control, and takes charge of transactions of an access layer; terminals, i.e., UEs, are various types of equipment which can communicate with a cellular wireless communication network.
As the communication industry has been developed up to now, there are various types of services; similarly, demands of customers become richer and richer, and requirements are higher and higher. Different services have different characteristics; for example, a position reporting terminal on a vehicle only needs to report the current position of the vehicle when the vehicle reaches a certain appointed location or according to an appointed period instead of communicating with a network all the time. Therefore, such a terminal has a power saving mode; under the power saving mode, sleep time is set; the terminal neither receive any paging message nor communicate with the network within the sleep time; the terminal can transmit and receive data and receive the paging message only within active time. At that time, when the network transmits a paging request to the terminal, the terminal will not feed back any information; when a response of the terminal cannot be obtained, the network will consider by a mistake that the terminal is off-line, and feed back wrong information to a system.